Yes, you can block spam. On the left under "My Settings" you have Anti-Spam. Check that it says "On". Junk mails will be sent to your Junk Mail folder. In the Inbox view there is a "Mark as Spam" button. You can make the spam filter work better for you by having addresses of friends in the "approved" list and addresses of junk senders in the "blocked" list.
If you also have an Orange mobile phone, you can also get your Orange email in Outlook Express.